JPH05261942A - Color printing method - Google Patents

Abstract

PURPOSE:To form the original picture element of an ink on a paper and perform a high picture quality printing by a method wherein after cleaning the vicinity of a discharge orifice by a cleaning member, an ink injection for non-printing is performed at least once. CONSTITUTION:When a carriage 101 moves to the right direction, the surfaces of discharge orifices 81B, 82C, 83M, 84Y comes into contact with a blade 113, and therefore, the surfaces of the discharge orifices 81B, 82C, 83M, 84Y of four color heads 93-96% are cleaned by the blade 113. When a head unit 97 passes in front of a recovery port 112, which is adjacent to the blade 113, at least once of ink jetting is performed from the discharge orifices 81B. 82C, 83M, 84Y of respective heads 93-96. The jetted unnecessary ink is jetted toward the recovery port 112 and recovered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color printing method, and more particularly to a color printing method capable of high quality printing by devising a treatment after cleaning an ejection orifice for ejecting ink of a plurality of colors. Regarding copying method.

[0002]

2. Description of the Related Art Conventionally, non-impact recording methods have been attracting attention because noise during recording is so small that they can be ignored. Among them, high-speed printing is possible, and so-called plain paper is specially fixed. The ink jet recording (liquid jet recording) method, which can perform recording without treatment, is an extremely effective recording method. Recently, various color printing methods using color ink have been proposed and improved. ing.

A conventional color printing method of this type is one in which droplets of ink of a plurality of colors are ejected and adhered to a recording member for recording, for example, Japanese Patent Publication No. 63-37.
There is one as described in Japanese Patent No. 50, which is shown as in FIG. In FIG. 16, a color inkjet head unit 1 includes a heating element substrate 2 having a heating resistor,
A plurality of color inks A, B, and C can be supplied alternately, and a grooved plate 3 in which liquid supply grooves arranged on the same surface are formed, and a plurality of color inks A, B, and C are liquid supply grooves. 4A, 4B, 4C and supply tubes 5A, 5B, 5C, and a printed circuit board 6 for applying an image signal, and a discharge orifice 7 for multicolor ink.
Form a multi-orifice array that is densely arranged.

In the color ink jet head unit 1 having such a structure, the supply block 4A,
Ink A of the three primary colors in the liquid supply groove through 4B and 4C
B and C are supplied, and the ink is adhered to the recording member by ejecting a small droplet of ink of a predetermined color from the discharge orifice 7 at a predetermined position by the electrothermal converter that is selectively driven. It has become.

On the other hand, in the color ink jet head unit 1 as described above, the inks A, B and C are continuously ejected from the ejection orifice 7 of the head 1 during the printing time during driving. Although the ejection orifice 7 is not clogged, the inks A, B, and C are not ejected from the ejection orifice 7 when the printing is stopped when the head 1 is not driven, and thus the ink remains in the ejection orifice 7 at the contact portion with the outside air. Dispersion of the inks A, B, and C due to evaporation of the solvent of the inks A, B, and C, resulting in clogging, and clogging due to inclusion of foreign matter such as dust in the outside air. Will occur.

For this reason, it is necessary to clean the surface of the discharge orifice 7 with a cleaning member to prevent the occurrence of ejection irregularity. For example, the cleaning member described in JP-A-62-9030 is used. It is conceivable to clean the surface of the discharge orifice 7. This cleaning member has a brush-shaped napped group and a liquid absorbing member on the outer peripheral portion of the rotating member, and cleans the surface of the discharge orifice 7 by bringing the cleaning member into contact with the discharge orifice 7. Therefore, in order to clean the surface of the ejection orifice 7 of the head 1 with this cleaning member, the cleaning member is used to clean the ejection orifice 7 surface.
By sequentially contacting the surface of the discharge orifice 7 with the cleaning member from one end side to the other end side in the arrangement direction of
It is possible to clean it.

[0007]

However, in the color ink jet head unit 1 described above,
The three color inks A, B, and C from the discharge orifice 7 are directed from one end side to the other end side in the arrangement direction A, B, C, A, B,
Since they are arranged so as to eject in the order of C, A, B, C, when the above-mentioned cleaning member is brought into contact with the surface of the discharge orifice 7, the ink wiped by the cleaning member is adjacent. There is a problem that the ink is mixed with the ink at the discharge orifice.

For this reason, the pixels on the paper surface ejected and molded by the first few drops of ink after being wiped off by the cleaning member do not become pixels of the original color of ink A (or ink B or ink C). However, a dirty pixel in which the ink B or the ink C is slightly mixed is formed, which causes a problem that the image quality is deteriorated.

Therefore, an object of the present invention is to provide a color printing method capable of always forming pixels of ink of the original color on the paper surface and performing high-quality printing.

[0010]

The invention according to claim 1 is
In order to solve the above-mentioned problems, a plurality of discharge orifices for ejecting a plurality of colors of ink for each color are integrated so as to be arranged on substantially the same plane and are movable in a predetermined direction with respect to a recording paper. A color inkjet head unit is used, and after cleaning the vicinity of the discharge orifice by bringing the cleaning member into contact with the vicinity of the discharge orifice by utilizing the relative movement with the head unit,
In a method of ejecting and printing a plurality of colors of ink, ink is ejected for non-printing after the vicinity of the ejection orifice is cleaned by the cleaning member and before the color inkjet head unit passes the front surface of the recording paper. Is performed at least once.

In order to solve the above-mentioned problems, a second aspect of the present invention uses a color ink jet head unit in which one nozzle plate is provided in each of the plurality of discharge orifices. According to a third aspect of the present invention, in order to solve the above problems, the color inkjet head unit is held by a carriage and is moved together with the carriage, so that the color ink jet head unit is moved relative to a cleaning member and a portion near an ejection orifice is provided. A color inkjet head unit is used which is brought into contact with the cleaning member and in which the plurality of ejection orifices for each color are not arranged in parallel with the predetermined direction.

[0012]

According to the first aspect of the present invention, after the vicinity of the discharge orifice is cleaned by the cleaning member and before the color ink jet head unit passes the front surface of the recording paper, at least one ink ejection for non-printing is performed. More than once. Therefore, after the ejection orifice is cleaned by the cleaning member, the mixed color ink is discarded from the ejection orifice, and the different color ink is not mixed when the ink is actually printed on the recording paper. For this reason, pixels of ink of mixed colors are not formed on the surface of the recording paper, and pixels are formed only of the ink of the original color, and high-quality printing is performed.

According to the second aspect of the present invention, there is used a color ink jet head unit in which one nozzle plate is provided for a plurality of ejection orifices. Therefore, the discharge orifice is formed by the common nozzle plate, the ejection of ink is stabilized, and the manufacturing cost of the head unit is reduced. Further, since one plate is attached to a plurality of ejection orifices, inks of different colors from adjacent ejection orifices are likely to be mixed on the surface of the orifice plate, and the pixels tend to be turbid in the initial stage of ejection. In the present invention, the ink ejection for non-printing is performed at least once before passing the front surface of the recording paper, so that the inks of different colors do not mix on the surface of the orifice plate, Pixels are formed only with the inks of color, and high-quality printing is performed.

In a third aspect of the invention, a color ink jet head unit is used in which a plurality of ejection orifices for each color are not arranged in parallel with a predetermined direction in which the recording paper is moved. Even in such a case, as in the case where a plurality of discharge orifices for each color are arranged in parallel with a predetermined direction in which the sheet moves with respect to the paper surface, it differs when the ink is actually printed on the recording paper. Colored ink does not mix.

That is, in the case where a plurality of ejection orifices for each color are arranged in parallel with a predetermined direction in which the sheet moves, when the head unit moves in the predetermined direction, the same color ink moves in the moving direction. On the other hand, since it contacts the cleaning member, there is no problem even if they are mixed, but if the ejection orifices for each color are not arranged in parallel with the predetermined direction in which they move with respect to the paper surface, the head unit will move in the predetermined direction. When the inks of different colors are moved, the inks of different colors come into contact with the cleaning member in the moving direction, so that the inks are mixed.

However, according to the present invention, at least one ink ejection for non-printing is performed before passing the front side of the recording paper.
Since the printing is performed more than once, the inks of different colors do not mix, the pixels are formed only by the inks of the original color, and high-quality printing is performed.

[0017]

EXAMPLES Examples of the present invention will be described below. First, an example of an inkjet head will be described with reference to FIGS. 8 is a diagram for explaining the operation of a bubble jet head as an example of an inkjet head, FIG. 9 is a perspective view showing an example of a bubble jet head,
FIG. 10 is a perspective view when disassembled into a lid substrate (FIG. 10 (a)) constituting the bubble jet head shown in FIG. 9 and a heating element substrate (FIG. 10 (b)), and FIG. 11 is shown in FIG. 8 is a perspective view of the lid substrate shown in FIG. 8) viewed from the back side, and in FIGS.
22 is a heating element substrate, 23 is a selection (independent) electrode, 24 is a common electrode,
25 is a heating element (heater), 26 is an adjacent ink layer (ink), 2
7 is a bubble, 28 is a flying ink drop, 29 is a recording liquid (ink)
Inflow port, 30 is a discharge orifice, 31 is a flow path, and 32 is a region for forming a liquid chamber.

First, ink ejection by a bubble jet will be described with reference to FIG. (a) is a steady state in which the surface tension of the ink 26 and the external pressure are in equilibrium on the orifice surface. In (b), the heater 25 is heated and heated until the surface temperature of the heater 25 rapidly rises and a boiling phenomenon occurs in the adjacent ink layer 26, and minute bubbles 27 are scattered.

(C) is a state in which the adjacent ink layer 26 that has been rapidly heated on the entire surface of the heater 25 is instantly vaporized to form a boiling film, and the bubble 27 is grown. At this time, the pressure in the nozzle rises by the amount of growth of the bubbles, the balance with the external pressure on the orifice surface is lost, and the ink column begins to grow from the orifice. In (d), the bubble 27 is grown to the maximum, and the ink 26 corresponding to the volume of the bubble is pushed out from the orifice surface. At this time, the heater 25 is in a state where no current flows, and the surface temperature of the heater 25 is decreasing. The maximum value of the volume of the bubble 27 is slightly delayed from the timing of applying the electric pulse.

(E) shows a state in which the bubble 27 is cooled by ink or the like and starts to contract. At the tip of the ink column, the ink column moves forward while maintaining the pushing speed, and at the rear end, ink contracts due to the contraction of the air bubbles, causing the ink to flow backward from the orifice surface into the nozzle, resulting in a constriction in the ink column. .. In (f), the bubble 27 is further contracted, the adjacent ink layer 26 is in contact with the heater 25 surface, and the heater 25 surface is further rapidly cooled. At the orifice surface, the external pressure is higher than the internal pressure of the nozzle, so a large meniscus has entered the nozzle. The tip of the ink column becomes an ink drop 28, which flies toward the recording paper at a speed of 5 to 10 m / sec.

(G) is a process in which the ink 26 is supplied (refilled) to the orifice again by the capillary phenomenon and returns to the state of (a), and the bubble 27 is completely extinguished. FIG. 12 is a view showing a typical example for explaining the configuration of the main part of the bubble jet head described above, and FIG. 12 (a) is a front detailed partial view seen from the orifice side of the bubble jet head, FIG. 12 (b). [Fig. 4] is a partial cross-sectional view of a cross section taken along one-dot chain line AA.

The bubble jet head 41 shown in these figures has a predetermined number of grooves with a predetermined width and depth at a predetermined linear density on a substrate 43 on the back surface of which an electrothermal converter 42 is provided. The grooved plate 44 provided is joined so as to cover the substrate 43, so that the liquid discharge part 46 including the orifice 45 for ejecting the liquid is formed.

In the liquid discharge part 46, the heat energy generated from the orifice 45 and the electrothermal converter 42 acts on the liquid to generate bubbles, which causes a rapid state change due to expansion and contraction of the volume. And an action portion 47. The heat acting portion 47 is located above the heat generating portion 48 of the electrothermal converter 42, and the heat acting surface 49 is a surface of the heat generating portion 48 that comes into contact with the liquid.
Is the low side.

The heat generating section 48 is composed of a lower layer 50 provided on the substrate 43, a heating resistance layer 51 provided on the lower layer 50, and an upper layer 52 provided on the heating resistance layer 51. To be done. The heating resistance device 51 is provided with electrodes 53 and 54 for energizing the layer 51 to generate heat, on its surface, and the heating generation layer 48 is formed by the heating resistance layer between these electrodes. ing.

The electrode 53 is an electrode common to the heat generating portion of each liquid ejecting portion, and the electrode 54 is a selection electrode for selecting the heat generating portion of each liquid ejecting portion to generate heat. It is provided along the liquid flow path of the part. The protection layer 52 is a liquid filling the liquid flow paths of the heat generation resistance layer 51 and the liquid discharge part 46 in order to chemically and physically protect the heat generation resistance layer 51 in the heat generation part 48 from the liquid used. It has the role of preventing short circuit between the electrodes 53 and 54 through the liquid and further preventing electrical leakage between adjacent electrodes.

The liquid flow paths provided in the respective liquid discharge parts are connected upstream of the respective discharge parts via a common liquid chamber (not shown) forming a part of the liquid flow paths. The electrodes 53 and 54 connected to the electrothermal converters 42 provided in the respective liquid discharge parts are protected by the upper layer for the convenience of the design, and are disposed under the common liquid chamber on the upstream side of the heat acting part. It is provided to pass.

FIG. 13 is a view for explaining the structure of the bubble generating means using a heating resistor, in which 61 is a heating resistor.
Is an electrode, 63 is a protective layer, 64 is a power supply device, and a heating resistor
Examples of useful materials for forming 61 include a tantalum-SiO2 mixture, tantalum nitride, nichrome,
Examples thereof include silver-palladium alloys, silicon semiconductors, and sulfides of metals such as hafnium, lanthanum, zirconium, titanium, tantalum, tungsten, molybdenum, niobium, chromium, and vanadium.

Among the materials composing these heating resistors 61, metal sulfides can be mentioned as particularly excellent ones. Among them, hafnium sulfide has the most excellent characteristics, and then sulfides. The order is zirconium, lanthanum sulfide, tantalum sulfide, vanadium sulfide, and niobium sulfide. The heating resistor 61 can be formed using the above materials by a method such as electron beam evaporation or sputtering. The film thickness of the heating resistor 61 is determined according to the area, the material, the shape and size of the heat acting portion, and the actual power consumption so that the amount of heat generated per unit time is as desired. However, usually 0.
001 to 5 μm, preferably 0.01 to 1 μm.

As the material forming the electrode 62, many of the commonly used electrode materials are effectively used, and specific examples thereof include Al, Ag, Au, Pt, Cu and the like. Using a method such as vapor deposition at a predetermined position,
It is provided with a predetermined size, shape, and thickness. The characteristic required for the protective layer 63 is that the heating resistor 61 is protected from the recording liquid without hindering the effective transfer of the heat generated by the heating resistor 61 to the recording liquid. Examples of useful materials for forming the protective layer 63 include silicon oxide, silicon nitride, magnesium oxide, aluminum oxide, tantalum oxide, zirconium oxide, and the like. Can be formed. The thickness of the protective layer 63 is usually
0.01-10 μm, preferably 0.1-5 μm, optimally 0.1-
It is desirable that the thickness is 3 μm.

FIGS. 14 and 15 are views showing another example of an ink jet head applied to the present invention, FIGS. 14 (a) and 14 (b) are principle diagrams thereof, and FIG. 15 is an example of a multi-orifice head. .. In FIGS. 14 and 15, 71 is a piezo element, 72 is an ink pressure chamber, 73 is an ejection orifice, 74 is a common ink chamber, 75 is a valve, 76 is an ink filter, 77 is an inkjet head, 78 is a print surface, and 79 is ink. It is a drop.

In this system, unlike the ink jet head of the above-mentioned system, a piezo element 71 which constitutes an electrostrictive vibrator is provided as an energy operating unit in the middle of the discharge orifice 73 and the ink supply source (common ink chamber 74). By applying a pulsed signal voltage to the piezo element 71 to distort the piezo element 71 and reduce the volume of the ink pressure chamber 72 to generate a pressure wave, an ink droplet 79 is ejected from the ejection orifice 73.
Is to be discharged. FIG. 15 constitutes a multi-orifice array by arranging a plurality of the piezo elements 71 shown in FIG.

FIG. 1 is a diagram showing a first embodiment of a color ink jet recording apparatus for achieving a color printing method according to the present invention, showing a color ink jet head unit. In FIG. 1, four inks of four colors, specifically, black (B), cyan (C), magenta (M), and yellow (Y) are provided for each color by stacking four heads shown in FIG. Multiple ejection orifices for injection 81
B, 82C, 83M and 84Y are arranged so as to be arranged on substantially the same plane, and discharge orifices 81B and 82
A bubble jet type color ink jet head unit 97 in which recording heads 93 to 96 including a pair of lid substrates 85 to 88 provided with C, 83M, and 84Y and heating element substrates 89 to 92 are integrated is shown.

As the head unit 97, an ink jet head using a piezo element as shown in FIG. 14 can be applied. FIG. 2 shows the head unit 97 described above.
1 shows a main part of a color ink jet recording apparatus in which is mounted. In the figure, 97 is the color inkjet head unit shown in FIG.
A storage unit that stores the ink supplied from the ink supply source, and a discharge orifice 81 that ejects the stored ink.
Recording heads 93 to 96 provided with B, 82C, 83M, and 84Y.

A cartridge tank as an ink supply source, which will be described later, can be attached to the carriage 102. Ten
Reference numeral 2 is a printed wiring board that controls ink ejection by the head unit 97, 103 is a flexible cable that connects the printed wiring board 102 and the head unit 97, and the printed wiring board 102 and the flexible cable 103 are connected via a connector. To do.

Reference numeral 104 denotes a paper feed motor, and the recording paper P is conveyed by the roller 105 in the direction f in the drawing in response to the drive of the paper feed motor 104. Reference numeral 106 denotes a roller that cooperates with the roller 105 to regulate the recording paper P flat and form a recording surface for the head unit 97. 107 is a belt for driving the carriage connected to the carriage 101, and 108 is the belt 107
Is a motor for driving in the S direction in the figure, and 109 is a guide rail of the carriage 101.

The carriage 101 moves in the predetermined direction S of the recording paper P along the guide rail 109 in response to the driving of the motor 108, and recording on the recording surface can be performed. 110 is a reliability maintaining mechanism, and the carriage 101
It is provided at the home position of. The maintenance mechanism 110 includes a main body 111, and a recovery port 112 that is opened in the main body 111 and collects the unnecessary ink when ejecting ink not used for printing (hereinafter, this printing is also referred to as non-printing). ,
A blade 113 as a cleaning member, which is provided to remove ink stains on the discharge orifices 81B, 82C, 83M, and 84Y surfaces, or stains such as paper dust and dust, and which is made of an elastic member, is opened in the main body 111, and is printed. And a cap mechanism 114 that covers the discharge orifices 81B, 82C, 83M, and 84Y when the image is stopped.

The blade 113 is fixed to the main body 111,
The fixed position is set so as to come into contact with the discharge orifices 81B, 82C, 83M and 84Y when the head unit 97 passes in front of the blade 113 by the movement of the carriage 101. Therefore, as the blade 113 and the carriage 101 move relative to each other, the surfaces of the discharge orifices 81B, 82C, 83M, 84Y come into contact with the blade 113 and are rubbed, and due to this contact, the discharge orifices 81B, 82C, 83M, 84Y are contaminated. Is wiped off.

The cap mechanism 114 recovers the printing function from the fact that the printing is not normally performed when printing is stopped or air bubbles are mixed into the discharge orifices 81B, 82C, 83M and 84Y, dust is adhered, ink is dried and the like. To this end, when the carriage 101 comes to the home position, it is slid in the direction of arrow A by a slide mechanism (not shown) so as to come into close contact with the ejection orifices 81B, 82C, 83M, 84Y surface to cover it.

Although four cap mechanisms 114 are independently provided in accordance with the ejection orifices 81 to 84 of each ink, the ejection orifices 81B, 82C, 83M and 84 are not independent.
It may be common so as to cover Y. Also, the cap mechanism 114 is simply a discharge orifice 81B, 82C, 8
Not only does it cover 3M and 84Y, but details are not shown,
After covering the discharge orifices 81B, 82C, 83M, 84Y, a vacuum pump is used to discharge the discharge orifices 81B, 82C, 83
The ink in M, 84Y or bubbles, dust, etc. may be sucked together with the ink.

Next, a color ink printing method according to the present invention will be described. First, since the carriage 101 is at the home position, the discharge orifice 81B,
The 82C, 83M, and 84Y surfaces are covered by the cap mechanism 114 and are kept in a sealed state. Next, when the maintenance mechanism 110 is retracted in the direction opposite to the arrow A direction, the carriage 101 moves to the right in FIG. At this time, the discharge orifice 81
Since the B, 82C, 83M, and 84Y surfaces contact the blade 113, the discharge orifices 81B, 82C of the four-color heads 93 to 96,
The 83M and 84Y surfaces are cleaned by the blade 113.

Next, the recovery port 112 adjacent to the blade 113
When the head unit 97 passes in front of the
Ink is ejected at least once from 96 ejection orifices 81B, 82C, 83M, 84Y. The unnecessary ink ejected at this time is ejected toward the recovery port 112 and recovered. After that, the carriage 101 moves to the front of the recording paper P and starts printing.

As described above, in the present embodiment, after cleaning the vicinity of the discharge orifices 81B, 82C, 83M and 84Y by the blade 113, before the head unit 97 passes the front surface of the recording paper P, non-printing is performed. Ink is ejected at least once. The reason why such ejection is performed is that when the ejection orifices 81B, 82C, 83M, 84Y of each color are cleaned by the blade 113 according to the movement of the carriage 101, the second and subsequent heads, for example, the first head Assuming that the head to be cleaned is the head 93 of black B and the second head is the head 94 of cyan C, the waste black B adhered to the head 93 at the ejection orifice 82C of the head 94.
Ink and the like adhere to the third and fourth ejection orifices 83M and 84Y and are sequentially transmitted.

For this reason, when inks of different colors are mixed or the discharge orifices 81B, 82C, 83M and 84Y are contaminated and printing is performed immediately after cleaning, pixels of the mixed color ink are formed on the recording paper P. This is because the flying direction of the ink is disturbed by dust or the like, and the pixel position accuracy on the surface of the recording paper P becomes very poor. In this embodiment, the ejection orifice 81B of the head unit 97 is discharged by performing non-printing before the recording paper P is passed.
After the 82C, 83M, and 84Y are cleaned by the blade 113, the mixed color ink is discarded from the ejection orifices 81B, 82C, 83M, and 84Y, and when the ink is actually printed on the recording paper P, different color inks are printed. Can be prevented from being mixed. As a result, it is possible to prevent pixels of ink of mixed colors from being formed on the surface of the recording paper P, and it is possible to form pixels with only the ink of the original color and perform high-quality printing. it can.

Table 1 shows the specific effect of the color printing according to the present embodiment, in which a non-printing ink is ejected from all the discharge orifices 81B, 82C, 83M and 84Y using a serial type color printer. These are the experimental results of In the present example, when non-printing ink ejection was performed three or more times, pixels without turbidity could be formed on the transfer paper P.

[0045]

[Table 1]

FIG. 3 is a diagram showing a second embodiment of a color ink jet recording apparatus for achieving the color printing method according to the present invention. In this embodiment, an example in which an orifice plate is provided for each discharge orifice is shown. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof is omitted. Because it has a common configuration,
A description will be given using the head 93.

The head 93 shown in the first embodiment is the flow path of FIG.
Although the tip of 31 constitutes the discharge orifice 81B as it is, an orifice plate 121 having a plurality of holes 121a corresponding to the discharge orifice 81B is attached to the head 93 on the side of the discharge orifice 81, and the discharge plate 81B is attached through this hole 121a. The discharge orifice 81 (that is, corresponding to the tip end portion of the flow path 31 in FIG. 11) is communicated with each other, and the plate 121 is independently provided to each of the heads 93 to 96.

The plate 121 can be formed by a technique such as photoetching or photoelectroforming. For example, a method of manufacturing the orifice plate 121 by Ni photoelectroforming is described in JP-A-54-87529. Such techniques can be used. Plate 121 like this
Since the head 93 to which is attached has excellent symmetry of the shape of the ejection orifice as compared with the head to which the orifice plate 121 is not attached, stable ink ejection (especially stability in ejection direction) can be performed. ..

FIG. 4 is a diagram showing a third embodiment of a color ink jet recording apparatus for achieving the color printing method according to the present invention. In this embodiment, a discharge orifice 81B,
An example in which one orifice plate is provided for the 82C, 83M, and 84Y is shown. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, the discharge orifices 81B, 82C, 83M and 84Y are connected to the heads 93 to 96 on the side of 81.
Attach one orifice plate 131 having a plurality of holes 131a corresponding to B, 82C, 83M and 84Y.
The discharge orifices 81 to 84 (that is, corresponding to the tip of the flow path 31 in FIG. 11) are communicated with each other via 31a.

In this embodiment, one orifice plate
Since 131 is provided, the manufacturing cost of the color inkjet head unit 97 can be reduced as compared with that described in the second embodiment. On the other hand, when one common plate 131 is provided in this way, adjacent inks of different colors are mixed on the surface of the orifice plate 131. This is because, in the head unit 97 shown in FIG. 1 or the head unit in which the heads 93 shown in FIG. 3 are stacked, the ejection orifice surfaces are temporarily independent for each color, whereas in the present embodiment. On the discharge orifice
Orifice plate 13 common to 81B, 82C, 83M and 84Y
In the case where 1 is provided, the inks of different colors easily contact the surface of the plate 131.

However, in the present embodiment, the blade 113 causes the holes 131a of the discharge orifices 81B, 82C, 83M and 84Y.
After cleaning the vicinity, and before the head unit 97 passes the front surface of the recording paper P, ink ejection for non-printing is performed at least once, so the ejection orifice 81B,
It is possible to discard the ink in which the colors 82C, 83M, and 84Y are mixed, and to form an image on the transfer paper P with the ink that does not have turbidity (mixing) during the actual printing.

Table 2 shows the specific effect of the color printing according to the present embodiment, in which a non-printing ink is ejected from all the ejection orifices 81B, 82C, 83M and 84Y using a serial type color printer. These are the experimental results at that time. In the present embodiment, it is possible to form pixels without turbidity on the transfer paper P when the non-printing ink ejection is performed twice or more, and it is slightly more effective than the one described in the first embodiment. I found it to be excellent.

[0053]

[Table 2]

5 to 7 show the relationship between the discharge orifice array for each color and the relative movement X of the blade. First,
As shown in FIG. 5, a plurality of discharge orifices 81 for each color are provided.
When B, 82C, 83M, and 84Y are arranged in parallel with the predetermined direction of movement with respect to the recording paper, the discharge orifices of the same color
Since 81B, 82C, 83M, and 84Y sequentially contact the blade 113, the probability that different colors are mixed is extremely low.

The discharge orifices 81B, 82 having such an arrangement
Experiments similar to those in the first and third embodiments were performed using C, 83M and 84Y. In this case, the pixels did not become turbid in color regardless of whether the discharge orifices 81B, 82C, 83M, and 84Y were cleaned by the blade 113. However, Figs.
, The discharge orifices 81B for each of the plurality of colors,
When the 82C, 83M, and 84Y are not arranged in parallel with the predetermined direction of movement with respect to the recording paper, the ink of the first color row adheres to the blade 113, and the blade 113 to which the ink adheres Since the color ejection orifice array is cleaned, ink is mixed in the ejection orifices.

For this reason, the discharge orifices 81B, 82
If the actual printing is immediately performed from C, 83M, and 84Y, pixels of the original color cannot be formed on the recording paper, and pixels of mixed colors are formed. However, in the present embodiment, after cleaning the vicinity of the ejection orifices 81B, 82C, 83M, 84Y by the blade 113 and before the head unit passes over the front surface of the color ink jet recording paper P, ink ejection for non-printing is performed. Since the ink is mixed at least once, it is possible to discard the ink in which the ejection orifices 81B, 82C, 83M, and 84Y are mixed, and an image is formed on the transfer paper P by the ink that does not have turbidity (mixing) during actual printing. be able to.

Table 3 shows the results when the same experiment as in the first and third embodiments was conducted with the discharge orifices having the arrangement shown in FIG. In FIG. 7, the ejection orifices 81B, 82C, 83M and 84Y are inclined unlike the ones shown in FIGS. 1 and 4 in order to improve the pixel density on the recording paper surface. In the present embodiment, it was possible to form pixels on the transfer paper P that were not turbid when the non-printing was performed once or more.

[0058]

[Table 3]

From the above experimental results, after cleaning the vicinity of the discharge orifices 81B, 82C, 83M and 84Y with the blade 113, before the color ink jet head unit passes the front surface of the recording paper, the non-printing is performed. When the ink is ejected at least once, it is possible to prevent the formation of pixels of ink of mixed colors on the surface of the recording paper, and the pixels are formed only with the ink of the original color to obtain a high quality print. Can be done.

[0060]

According to the first aspect of the present invention, after the ejection orifice of the color ink jet head unit is cleaned by the cleaning member, the ink mixed with colors can be discarded from the ejection orifice, and the ink is not recorded on the recording paper. It is possible to prevent the inks of different colors from being mixed with each other when the actual printing is performed. As a result, it is possible to prevent pixels of ink of mixed colors from being formed on the surface of the recording paper, and it is possible to form pixels with only the ink of the original color and perform high-quality printing.

According to the second aspect of the present invention, the discharge orifice can be formed by the common nozzle plate, the ink ejection can be stabilized, and
The manufacturing cost of the head unit can be reduced.
According to the third aspect of the invention, when the ink is actually printed on the recording paper, as in the case where the plurality of ejection orifices for each color are arranged in parallel with the predetermined direction moving with respect to the paper surface. It is possible to prevent the inks of different colors from being mixed with each other. As a result, pixels can be formed only with the ink of the original color, and high-quality printing can be performed.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of a color inkjet recording apparatus for achieving a color printing method according to the present invention, and is a perspective view of the color inkjet head unit.

FIG. 2 is a diagram illustrating a main part of the inkjet printer according to the first embodiment.

3A and 3B are views showing a second embodiment of a color ink jet recording apparatus for achieving a color printing method according to the present invention, FIG. 3A is an exploded perspective view of a head and an orifice plate, and FIG. It is a perspective view of a head in which an orifice plate is attached to an orifice.

4A and 4B are views showing a third embodiment of a color ink jet recording apparatus for achieving the color printing method according to the present invention, FIG. 4A is an exploded perspective view of a head plate and a head unit, and FIG. It is a perspective view of a head unit in which an orifice plate is attached to a discharge orifice.

FIG. 5: The discharge orifice is the moving direction X of the head unit.
It is a figure showing what was arranged in parallel with.

FIG. 6 shows the discharge orifice in the moving direction X of the head unit.
It is a figure which shows what is not arrange | positioned in parallel with.

FIG. 7: The discharge orifice is the moving direction X of the head unit.
It is a figure which shows what is not arrange | positioned in parallel with.

FIG. 8 is a diagram illustrating the principle of ink ejection by a bubble jet.

FIG. 9 is a perspective view showing an example of a bubble jet head.

10A is a perspective view of a lid substrate that constitutes the bubble jet head shown in FIG. 9, and FIG. 10B is a perspective view of the heating element substrate shown in FIG.

11 is a perspective view of the lid substrate shown in FIG. 10 (a) as viewed from the back side.

FIG. 12 (a) is a detailed front partial view of the bubble jet head as viewed from the orifice side, and FIG. 12 (b) is a partial cut surface view taken along the chain line AA.

FIG. 13 is a diagram showing a structure of a bubble generating means using a heating resistor.

FIG. 14 is a diagram showing another example of an inkjet head.

FIG. 15 is a diagram showing a multi-orifice head.

FIG. 16 is a configuration diagram of a conventional color inkjet head unit.

[Explanation of symbols]

 81B, 82C, 83M, 84Y Discharge orifice 97 Color inkjet head unit 101 Carriage 113 Blade (cleaning member) 121, 131 Orifice plate P Recording paper

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication location H04N 1/034 9070-5C 1/23 101 C 9186-5C 8306-2C B41J 3/04 102 Z

Claims (3)

[Claims] 1. A color ink jet which is integrated so that a plurality of ejection orifices for ejecting a plurality of colors of ink for each color are arranged in substantially the same plane and is movable in a predetermined direction with respect to a recording paper. A head unit is used, and a cleaning member is brought into contact with the vicinity of the ejection orifice by utilizing relative movement with the head unit to clean the vicinity of the ejection orifice and then eject and print a plurality of colors of ink. In the method, after cleaning the vicinity of the discharge orifice by the cleaning member, ink is ejected at least once for non-printing before the color inkjet head unit passes over the front surface of the recording paper. Color printing method. 2. The color printing method according to claim 1, wherein a color ink jet head unit in which one nozzle plate is provided for the plurality of discharge orifices is used. 3. The color ink jet head unit is held by a carriage and is moved together with the carriage, so that the color ink jet head unit is moved relative to a cleaning member so that the vicinity of an ejection orifice is brought into contact with the cleaning member. 3. The color printing method according to claim 1, wherein a color ink jet head unit in which the discharge orifices for each color are not arranged in parallel with the predetermined direction is used.